The present invention relates to an improved breathing device for delivering air under pressure to nasal passages in the treatment of breathing disorders, such as sleep apnea, ventilation difficulties or anesthetic gas administration. Sleep related breathing disorders adversely affect the breathing of individuals during periods of sleep. Sleep related breathing disorders include difficulties in sleeping, snoring, and more serious conditions, such as sleep apnea. Sleep apnea is the temporary cessation of breathing during sleep. Persons suffering from sleep apnea can stop breathing for periods as short as a few seconds, to as long as several minutes. Sleep apnea is a common disorder, affecting about a quarter of all middle-aged men in the United States, and about ten percent of middle-aged women. There are several forms of sleep apnea, including obstructive sleep apnea, central sleep apnea and mixed sleep apnea. Obstructive sleep apnea results when the flow of air in and out of the airways is blocked by upper airway obstruction. This form of sleep apnea is marked by loud snorting, snoring and gasping sounds during sleep. Central sleep apnea is caused by the absence of respiratory muscle activity. Persons suffering from this sleep apnea may exhibit excessive daytime sleepiness. Mixed apnea begins with the absence of respiratory effort and is followed by upper airway obstruction. Prolonged sleep apnea can result in headache, fatigue, and drowsiness. Other disorders include nighttime thrashing, sleepwalking, enuresis, disorientation, personality changes, intellectual deterioration, sexual dysfunction, and hypnagogic hallucinations.
Typically sleep apnea is treated by Continuous Positive Air Pressure (CPAP). For such therapy a device that forces air into an individual's air passageway to affect a slightly positive pressure of air to the nasal passages. The application of a slightly positive pressure of air is typically effective in reversing airway obstruction in patients suffering from obstructive sleep apnea.
Typically, a person suffering from sleep apnea must use CPAP therapy on a regular basis to prevent the reoccurrence of the sleep disorder. The patient typically wears a mask-like device that is connected to a CPAP device that provides an elevated or slightly positive air pressure into a patient's upper air passageway. Problems associated with wearing existing masks during periods of sleep are sufficient to deter many patients from continuing CPAP therapy. The most common problem associated with CPAP mask systems in use today is loss of the air seal between the mask and the user's face. This results in a loss in pressure, and, thereby, jeopardizes the effectiveness of the CPAP therapy. If the user is asleep and unaware of the escaping air, severe burns can occur to the skin. If the stream of pressurized air happens to be directed toward an eye, severe burns to the eyelid and surrounding tissue may occur, resulting in the eye being swollen shut.
Adjustable straps are commonly used to secure the mask to the patient's face. The straps are usually made from an elastic material. There are usually two to three straps attached to the mask. It is frequently difficult to adjust the straps sufficiently so as to hold the mask in the proper position on the user's face. The more straps attached to the mask, the harder it is to properly adjust them so that they are in equilibrium. In an attempt by the user to adjust the straps so as to hold the mask in place during movements that occur during a full night of sleep, the straps are pulled so tightly that the mask becomes very uncomfortable. The excessive pressure exerted by the mask usually causes red areas on the face and sometimes even causes blisters. Heavy pressure is not only uncomfortable, but actually distorts the elastomeric portion of the mask that makes contact with the user's face making it more difficult to maintain an air seal.
Various designs have been proposed to overcome some of these problems. See for example U.S. Pat. Nos. 6,012,455; 6,192,886; 6,209,542; 6,244,865; 6,305,379; 6,341,060 and 6,374,824; (the disclosures of which are incorporated herein by reference). However, these devices are not entirely satisfactory. The problems with improperly fitting masks are so severe that typically 50 percent of people who try CPAP therapy reject it.
Accordingly, there is a need for a device that permits a stable seating of a breathing device during the treatment of a breathing disorder that is also comfortable to wear during periods of sleep. This in turn will result in more effective treatment of breathing disorders, such as sleep apnea.